We look at the division of 39718502 by 645 
The aim is to understand the frequency of 645 in 39718502.

Going ahead to step 1:
645 goes into 3 0 times with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 645

Going ahead to step 2:
645 goes into 39 0 times with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 39 to get 39.
Grab the next digit (7) from the dividend, add it to 39, then carry on: 397 / 645

Going ahead to step 3:
The number 645 fits into 397 0 times, leaving a remainder of 397.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 397, we end up with 397.
Append the next digit (1) from the dividend to 397 and continue with: 3971 / 645

Going ahead to step 4:
645 goes into 3971 6 times with a remainder of 101.
Use 6 as the next digit of our solution. 
Result so far: 6.0
If we subtract 3870 from 3971, we get 101.
Include the next digit (8) from the dividend after 101, then repeat: 1018 / 645

On to step 5:
The number 645 fits into 1018 1 times, leaving a remainder of 373.
The number 1 becomes the next digit in our result. 
Result so far: 61.0
Subtract 645 from 1018 to get 373.
Grab the next digit (5) from the dividend, add it to 373, then carry on: 3735 / 645

Let's proceed to step 6:
When dividing 3735 by 645, we get 5 with a remainder of 510.
The number 5 becomes the next digit in our result. 
Result so far: 615.0
The remainder is 510 after subtracting 3225 from 3735.
Grab the next digit (0) from the dividend, add it to 510, then carry on: 5100 / 645

Advancing to step 7:
645 can be fit into 5100 7 times, resulting in a remainder of 585.
Use 7 as the next digit of our solution. 
Result so far: 6157.0
If we subtract 4515 from 5100, we get 585.
Take the next digit (2) from the dividend and append it to 585, then repeat: 5852 / 645

Going ahead to step 8:
5852 divided by 645 is 9 with a remainder of 47.
Record the quotient 9 as the next digit in the result. 
Result so far: 61579.0
Deduct 5805 from 5852 and we're left with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Let's proceed to step 9:
645 goes into 470 0 times with a remainder of 470.
The next digit of our result is 0. 
Result so far: 61579.0
The remainder is 470 after subtracting 0 from 470.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4700, and continue the process.

Advancing to step 10:
If we divide 4700 by 645, we get 7 and a remainder of 185.
Record the quotient 7 as the next digit in the result. 
Result so far: 61579.07
If we subtract 4515 from 4700, we get 185.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1850, and continue the process.

Step 11:
645 can be fit into 1850 2 times, resulting in a remainder of 560.
Record the quotient 2 as the next digit in the result. 
Result so far: 61579.072
If we take 1290 away from 1850, we end up with 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

Let's proceed to step 12:
5600 divided by 645 is 8 with a remainder of 440.
Write down 8 as next digit of the result. 
Result so far: 61579.0728
The remainder is 440 after subtracting 5160 from 5600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Let's proceed to step 13:
645 can be fit into 4400 6 times, resulting in a remainder of 530.
Record the quotient 6 as the next digit in the result. 
Result so far: 61579.07286
If we subtract 3870 from 4400, we get 530.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5300, and continue the process.

On to step 14:
645 can be fit into 5300 8 times, resulting in a remainder of 140.
The number 8 becomes the next digit in our result. 
Result so far: 61579.072868
The remainder is 140 after subtracting 5160 from 5300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1400, and continue the process.

Let's proceed to step 15:
If we divide 1400 by 645, we get 2 and a remainder of 110.
The number 2 becomes the next digit in our result. 
Result so far: 61579.0728682
If we subtract 1290 from 1400, we get 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

Advancing to step 16:
When dividing 1100 by 645, we get 1 with a remainder of 455.
The number 1 becomes the next digit in our result. 
Result so far: 61579.07286821
The remainder is 455 after subtracting 645 from 1100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4550, and continue the process.

The final outcome is 61579.07286821, with a leftover of 4.55e-07.